Slaughterhouse closing, chainsaw going spare. So ends the backstory of this slick, cash-in prequel to the remake of Tobe Hooper's horror classic. Here is a tale that purports to uncover the traumas that spawned a family of carnivores but is really just an excuse for blood-soaked business as usual, sending a quartet of shrilling teens through the obligatory old dark house. I'm not sure what was more unnerving: The Beginning's cackling sadism or its rank cynicism. After seeing her teen cohorts variously hog-tied, stuck and gutted, lissom Jordana Brewster sticks her rear in the air and crawls along the porch as though she's dunking for dollars. Which in a sense she is.